Development of a cardiac catheter for intracardiac ultrasound diagnostic imaging is proposed for monitoring heart function in perioperative critical care settings where chest wall echo is unavailable; for anatomical and functional monitoring of cardiac catheterization interventions for coronary artery disease, valvular disease and congenital heart disease; and for monitoring, controlling cardiac arrhythmias by electrophysiologic or ablation therapies. Application of these devices would replace transesophageal echo in patients needing the above therapies. The goals of this Phase I application are to define the specifications, applicability, and commercial viability of new "high-risk" technologies applied toward the development of the OEM marketed intraluminal ultrasound probes for those companies in the commercial cardiac ultrasound market. Our probes will be designed for placement in the heart from which they would produce high resolution images of the entire heart or portions of it as well as ablation procedures used for Doppler flow information. PROPOSED COMMERCIAL APPLICATIONS: This intracardiac ultrasound imaging catheter is to be an OEM product intended to reside as a feature within a full-capability, color Doppler, high- end echocardiography machine. The catheter is to be capable of monitoring heart function as well as catheter interventions. This functionality matches that of current transesophageal methods but will provide higher resolution.